O2 Sensor Predicament

[BigBird]

This is on a '94 K1500 with the 350 tbi. (Engine is from a '93 and bored .030 over)

The guy I got this truck from put in a dual exhaust system with no cats and no bungs to put in o2 sensors.
I've always got pretty poor fuel mileage from this truck. I figured that's just how it was. One day a coworker of mine told me that I should put in an o2 sensor because he gets better gas mileage than I do with the same motor (besides the over bore).

My question is this: Should I find an aftermarket exhaust coupler with an o2 bung in it? Or should I try to find one of those o2 sensor simulators?

I would drive it more if it didn't kill gas like I kill tacos!

 

[kennythewelder]

A simulator is used to trick the ECM into reading the rear 02 sensor, not the front. The front 02 sensor is what adjust fuel trim ratios. The original exhaust system only had 1,,, 02 sensor in 1994. If you want to keep the dual exhaust system, you could install a X pipe, and install a bung there. There were no rear 02 sensors used until 1996 on the OBD 2 ECM systems. You have an OBD 1 system, they were in trucks from 1988 through 1995.

 

[Schurkey]

The original exhaust system only read the O2 from the driver's side bank.

You need someone to weld-in an O2 bung on the driver's side header collector. Install a sensor, plug it into the existing wire. (Assuming he didn't remove the O2 wire going back to the ECM.)

How is this truck NOT setting a code due to the lack of O2 sensor information? What else did the prior owner screw-up?